1. Field of the Invention
This invention relates to denture adhesives or stabilizers, and particularly to an improved anhydrous denture adhesive composition.
2. Description of the Prior Art
Traditionally, adherent powders used to secure dentures within the mouth were prepared from such materials as finely powdered natural gums, i.e. karaya, acacia or tragacanth gum. These materials have the particular property of swelling to many times their original volume upon the addition of water to form a gelatinous or mucilaginous mass. Denture adhesive powders may be a combination of one or more natural gums, generally flavored with pleasant tasting volatile oils. Many other additives may also be included, such as antiseptics, stabilizers, bactericides, special deodorants, plasticizing agents, fillers, coloring agents, and the like.
Cream forms of the denture adherent, prepared from finely ground particles of the natural gums dispersed in a cream base, are also available and may be used instead of the powder compositions. In any event, when wet with water, the natural gum in either the cream or powder formulation expands to become a viscous gel which acts as a cushion and an adherent between the denture plate and the gum tissue.
While these relatively simple formulations are effective in securing dentures within the oral cavity for a short period of time, generally more than one application of adhesive per day is necessary. This is, at best, inconvenient and therefore, most undesirable.
In recent years, there have been numerous improvements in the above-described simple denture adhesive formulations. For example, U.S. Pat. No. 3,736,274 discloses a denture adhesive containing three essential ingredients: a maleic anhydride and/or acid copolymer (with a lower alkyl vinyl ether), a polymeric N-vinyl lactam, and sodium carboxymethylcellulose (CMC), preferably incorporated into a diluent such as petrolatum and/or mineral oil. The patent discloses that the CMC acts in a way to prevent the maleic anhydride copolymer N-vinyl lactam complex from precipitating when placed in water.
U.S. Pat. No. 4,280,936 discloses a denture adhesive comprising sodium carboxymethylcellulose and poly (ethylene oxide) homopolymer in a mineral oil base.
U.S. Pat. No. 4,514,528 is directed to a hydrophilic denture adhesive which consists of an admixture of mixed, partial salts of lower alkyl vinyl ether-maleic anhydride-type copolymers with either sodium carboxymethylcellulose or poly (ethylene oxide) homopolymer or both in a hydrophilic vehicle.
U.S. Pat. No. 4,518,721 discloses a denture adhesive which consists of sodium carboxymethylcellulose and poly (ethylene oxide) in a hydrophilic vehicle comprising certain polyethylene gylcols and, optionally, glycerin.
U.S. Pat. No. 4,569,955 discloses a denture adhesive containing an adhesive polymeric fraction comprising an admixture of mixed, partial salts of lower alkyl vinyl ether-maleic anhydride-type copolymers with sodium carboxymethylcellulose in a mineral oil vehicle thickened with polyethylene having a molecular weight of 1,000 to 21,000.
U.S. Pat. No. 4,373,036 discloses a denture fixative composition containing a dentally acceptable excipient and an effective fixative amount of a fixative mixture comprising hydroxypropyl cellulose and at least one partially neutralized alkyl vinyl ether-maleic acid or anhydride copolymer, optionally partly crosslinked, or a partially neutralized, optionally partly crosslinked polyacrylic acid or a precursor combination of the copolymer or polyacrylic acid, neutralizing agents, and optionally crosslinking agents such as calcium and magnesium.
U.S. Pat. No. 4,521,551 discloses a denture fixative composition containing denture fixative excipients and as the denture fixative, a water soluble partially neutralized alkyl vinyl ether-maleic acid or anhydride copolymer, optionally partly crosslinked with a polyhydroxyl compound, and at least one hydrophilic polymer, preferably sodium carboxymethylcellulose, polyethylene oxide or hydroxypropyl guar.
While the above denture adhesives provide some improvement over simple formulations containing only finely powdered natural gums, it is generally recognized that no one product has yet been developed which can accommodate over a long period of time, the many variations in temperatures, pH and mechanical agitation which are quite normal in the oral cavity.
It has now been found that the denture adhesive of this invention will provide superior adherent properties over prolonged periods of time and under unusually varied conditions, without the disadvantages characteristic of previously known products.